Question 1

What would happen if the G-protein coupled receptor in heart cells that binds to ACh had a mutation that caused it to bind more tightly to the G-protein alpha subunit?

Accepted Answer

A)  G-protein activation and K+ channel opening would happen more quickly.Heart rate may remain abnormally low,impairing response to stress.
B)  This would lead to K+ flow out of heart cells,causing increased hyperpolarization.
C)  G-protein activation and K+ channel opening would be slowed.Heart rate may remain abnormally high,especially following stress.
D)  This would lead to K+ flow into heart cells,causing increased depolarization.E) All of the above
F) B) and C)

Question 2

The membrane of a resting neuron is most permeable to which of the following ions?

Accepted Answer

A)  Cl-
B)  Ca2+
C)  Na+
D)  K+
E)  H+F) D) and E)
G) B) and E) D

Question 3

Choose the two primary factors that contribute to the resting membrane potential of a neuron.

Accepted Answer

A)  K+ leak channels make the cell membrane more permeable to K+.
B)  The sodium-potassium pump exports 3 K+ from the cell for every 2 Na+ it imports
C)  Na+ leak channels make the cell membrane more permeable to Na+.
D)  K+ leak channels cause a higher concentration of K+ outside the cell.
E)  The sodium-potassium pump exports 3 Na+ from the cell for every 2 K+ it importsF) B) and C)
G) A) and B) A,E

Question 4

What are the branched extensions of a neuron that receive signals called?

Accepted Answer

A)  axons
B)  cell bodies
C)  dendrites
D)  oligodendrocytes
E)  synapsesF) B) and D)
G) C) and E) C

Question 5

In early vertebrates,which component of the brain was devoted largely to coordinating motor reflexes?

Accepted Answer

A)  thalamus
B)  forebrain
C)  midbrain
D)  hindbrain
E)  medulla oblongataF) A) and E)
G) C) and E)

Question 6

If K+ can exit the cell through leak channels,why don't they flow out until there are equal concentrations on both sides of the membrane?

Accepted Answer

A)  K+ can act as an enzymatic cofactor,and most K+ ions are bound to cellular enzymes.
B)  The leak channels allow a very slow leak that cannot keep pace with active import of K+ ions.
C)  Chelator molecules trap K+ on the inside of the membrane.
D)  The negative electrical potential inside the cell creates a force that holds the K+ ions in.E) None of the above
F) A) and B)

Question 7

Mutation of the peripheral myelin protein 22 (PMP22) gene,which causes demyelination of peripheral neurons,is a more common cause of Charcot-Marie-Tooth disease.In which cells is the PMP22 gene important for normal function?

Accepted Answer

A)  Schwann cells
B)  preganglionic neurons
C)  postganglionic neurons
D)  oligodendrocytes
E)  interneuronsF) A) and D)
G) All of the above

Question 8

Subsequent to motor neuron degeneration in Charcot-Marie-Tooth disease,muscles begin to weaken and degenerate as well.What is the likely cause?

Accepted Answer

A)  Muscles will atrophy if they don't receive regular stimulation from motor neurons.
B)  Muscles require healthy Schwann cells for myelination as well.
C)  Muscles contain large numbers of mitochondria.
D)  Toxins leak out from the dying motor neurons onto the muscles.E) C) and D)
F) B) and D)

Question 9

What limits the frequency of action potentials?

Accepted Answer

A)  chloride ions
B)  spike amplitude
C)  nodes of Ranvier
D)  refractory periodE) C) and D)
F) B) and D)

Question 10

Since there is a larger concentration of potassium ions inside a neuron,why is the inside of the neuron negative (-70mV) relative to the outside?

Accepted Answer

A)  Potassium ions carry a negative charge.
B)  Negatively-charged proteins inside the cell counteract the charge of the potassium ions.
C)  The negative sign is just a historical convention.
D)  The high concentration of sodium ions outside the cell makes the inside negative by comparison.E) B) and D)
F) B) and C)

Question 11

The hippocampus,amygdala,and hypothalamus are the major components of the ________ system.

Accepted Answer

A)  sympathetic
B)  reflex
C)  parasympathetic
D)  limbic
E)  autonomicF) C) and E)
G) None of the above

Question 12

Which of the following is NOT a feature of the limbic system?

Accepted Answer

A)  contains hippocampus and amygdala
B)  resides deep within the cerebrum
C)  responsible for emotional responses
D)  important in the formation and recall of memories
E)  part of the hypothalamusF) A) and E)
G) C) and E)

Question 13

Genetic studies have found that Charcot-Marie-Tooth may be caused by a mutation in the gene Mitofusin-2 (MFN2) ,which causes mitochondria to form large clumps.In what area of a neuron are these clumps most likely to cause a problem?

Accepted Answer

A)  axon
B)  synapse
C)  soma
D)  dendrite
E)  myelinF) B) and D)
G) A) and C)

Question 14

What are examples of cells that support neurons both structurally and functionally?

Accepted Answer

A)  dendrites and nodes of Ranvier
B)  neuroglia and nodes of Ranvier
C)  Schwann cells and dendrites
D)  dendrites,nodes of Ranvier,and neuroglia
E)  Schwann cells,oligodendrocytes,and other neurogliaF) A) and E)
G) A) and D)

Question 15

Which division of the nervous system regulates the activity of smooth muscle,cardiac muscle,and glands?

Accepted Answer

A)  antagonistic nervous system
B)  autonomic nervous system
C)  sympathetic nervous system
D)  parasympathetic nervous system
E)  limbic nervous systemF) B) and D)
G) All of the above

Question 16

Another toxin that also blocks neurotransmitter release is tetanus toxin; however,it primarily affects inhibitory interneurons of the spinal cord that negatively regulate motor neurons.Which would be symptoms of tetanus toxin poisoning?

Accepted Answer

A)  flaccid paralysis
B)  spastic paralysis
C)  slowed action potential conduction
D)  pupil dilationE) A) and B)
F) B) and C)

Question 17

You dissect the brain of a mutant mouse and find that parts of the "white matter" look gray.What is a likely cause?

Accepted Answer

A)  defects in myelination
B)  peripheral nerve damage
C)  oversized dendrites
D)  excess myelination
E)  excess neuronal proliferationF) A) and E)
G) C) and E)

Question 18

What region of the brain integrates visceral activities,body temperature,and heartbeat?

Accepted Answer

A)  medulla oblongata
B)  cerebrum
C)  hypothalamus
D)  thalamus
E)  corpus callosumF) A) and B)
G) B) and D)

Question 19

What is the likely impact of this toxin on action potentials?

Accepted Answer

A)  They will occur more frequently.
B)  They will be stronger and more unpredictable.
C)  Without ion gradients,action potentials are not possible.
D)  They will have longer refractory periods.E) All of the above
F) A) and D)

Question 20

Which of the following structures is NOT a component of the hindbrain?

Accepted Answer

A)  pons
B)  medulla oblongata
C)  ascending tracts
D)  cerebellumE) A) and B)
F) B) and D)

Exam 42: The Nervous System

What would happen if the G-protein coupled receptor in heart cells that binds to ACh had a mutation that caused it to bind more tightly to the G-protein alpha subunit?

Correct AnswerverifiedShow Answer

The membrane of a resting neuron is most permeable to which of the following ions?

Correct AnswerverifiedD

Choose the two primary factors that contribute to the resting membrane potential of a neuron.

Correct AnswerverifiedA,E

What are the branched extensions of a neuron that receive signals called?

Correct AnswerverifiedC

In early vertebrates,which component of the brain was devoted largely to coordinating motor reflexes?

Correct AnswerverifiedShow Answer

If K+ can exit the cell through leak channels,why don't they flow out until there are equal concentrations on both sides of the membrane?

Correct AnswerverifiedShow Answer

Mutation of the peripheral myelin protein 22 (PMP22) gene,which causes demyelination of peripheral neurons,is a more common cause of Charcot-Marie-Tooth disease.In which cells is the PMP22 gene important for normal function?

Correct AnswerverifiedShow Answer

Subsequent to motor neuron degeneration in Charcot-Marie-Tooth disease,muscles begin to weaken and degenerate as well.What is the likely cause?

Correct AnswerverifiedShow Answer

What limits the frequency of action potentials?

Correct AnswerverifiedShow Answer

Since there is a larger concentration of potassium ions inside a neuron,why is the inside of the neuron negative (-70mV) relative to the outside?

Correct AnswerverifiedShow Answer

The hippocampus,amygdala,and hypothalamus are the major components of the ________ system.

Correct AnswerverifiedShow Answer

Which of the following is NOT a feature of the limbic system?

Correct AnswerverifiedShow Answer

Genetic studies have found that Charcot-Marie-Tooth may be caused by a mutation in the gene Mitofusin-2 (MFN2) ,which causes mitochondria to form large clumps.In what area of a neuron are these clumps most likely to cause a problem?

Correct AnswerverifiedShow Answer

What are examples of cells that support neurons both structurally and functionally?

Correct AnswerverifiedShow Answer

Which division of the nervous system regulates the activity of smooth muscle,cardiac muscle,and glands?

Correct AnswerverifiedShow Answer

Another toxin that also blocks neurotransmitter release is tetanus toxin; however,it primarily affects inhibitory interneurons of the spinal cord that negatively regulate motor neurons.Which would be symptoms of tetanus toxin poisoning?

Correct AnswerverifiedShow Answer

You dissect the brain of a mutant mouse and find that parts of the "white matter" look gray.What is a likely cause?

Correct AnswerverifiedShow Answer

What region of the brain integrates visceral activities,body temperature,and heartbeat?

Correct AnswerverifiedShow Answer

What is the likely impact of this toxin on action potentials?

Correct AnswerverifiedShow Answer

Which of the following structures is NOT a component of the hindbrain?

Correct AnswerverifiedShow Answer

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If K⁺ can exit the cell through leak channels,why don't they flow out until there are equal concentrations on both sides of the membrane?

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